Article continues below advertisementNicole Kidman showed off her natural curly hair while celebrating daughter Faith's 15th birthday, marking a rare departure from her usual sleek styles.The actress, 58, shared a sweet photo to Instagram Stories on Sunday, December 28, holding a birthday cake and wearing a festive "Happy Birthday" headband, letting her blonde curls fall loose.Article continues below advertisementSource: @nicolekidman/InstagramNicole Kidman showed off her natural curly hair while celebrating daughter Faith's 15th birthday, marking a rare departure from her usual sleek styles.